A fiber optic sensor with which the curvature of a body or a mechanical component can be determined is known from US 2007/0297712 A1. For this purpose, the fiber optic sensor has a plurality of cores which are surrounded by a common cladding. Bragg gratings are disposed in the cores, so that different mechanical compressive and tensile stresses can be determined if the fiber is curved. The curvature of the fiber, and with it the position of the fiber end in the space, can be thus be determined.
This known fiber optic sensor has the disadvantage, however, that the measurement values can be corrupted by torsion of the sensor about its longitudinal axis. The known sensor is not suited to distinguish between torsion and curvature, because they both result in the same change in the lattice constants of the Bragg grating.